1. Field of the Invention
The present invention relates to a camera of a preliminary winding type in which a film stored in a patrone is previously taken out from the patrone and rolled round a spool and the film is rolled back frame by frame from the spool for photographing.
2. Description of the Related Art
Recently, electric motorization has been progressed in a camera. For example, frame-by-frame film advancing in photographing, film rewinding after completion of photographing, adjustments of focal distances and the like have been motor-operated. However, in a camera of an ordinary winding type which has a focal length varying mechanism such as a zoom mechanism, a tele-wide switching mechanism and the like, if an exclusive motor for adjusting focal distances in an electric powered manner, besides a motor for frame-by-frame advancing/film rewinding, is provided in the camera, then the camera becomes inconveniently larger in size.
Also, when the frame-by-frame advancing mechanism, film rewinding mechanism and focal distance varying mechanism are driven by a single motor, a three-way switchable clutch device is necessary which is complicated in mechanism.
Conventionally, in the field of the camera of an ordinary winding type, there is proposed a camera (Japanese Utility Model Kokkai (Laid-open) No. 60-110835 in which first clutch for switching a frame-by-frame film advancing mechanism and a film rewinding mechanism and a second clutch for switching a film rewinding mechanism and a focal distance varying mechanism are employed and the frame-by-frame advancing mechanism, film rewinding mechanism and focal distance varying mechanism can be switched selectively by the two clutches. In this camera, at first the first clutch is switched to the frame-by-frame mechanism to advance a film by one frame, next the first clutch is switched from the frame-by-frame advancing mechanism over to the film rewinding mechanism and the second clutch is switched over to the focal distance varying mechanism for driving lens, and, after a shutter is released, the first clutch is again switched over to the frame-by-frame mechanism. After then, these operations are repeated until all frames of the film are photographed. After completion of photographing, the first clutch is switched over to the rewinding mechanism and the second clutch is changed over to the rewinding mechanism so that the film can be rewound.
However, the above-mentioned camera of an ordinary winding type is disadvantgeous in that it requires an external operation member for switching the second clutchand that it requires a complicated switching mechanism between the external operation member and itself.
On the other hand, there has been proposed a camera of a preliminary winding type in which the whole length of a film stored in a patrone is previously reeled around a spool, each time the photographing of each frame is completed the film is rewound into a patrone to feed the frame, and this operation is repeated until the whole length of the film is photographed.
The camera of the above-mentioned preliminary winding type comprises a preliminary winding mechanism which previously draws out a film stored in a patrone therefrom and rolls the film around a spool, and a frame-by-frame film rewinding mechanism for rewinding the film frame by frame from the spool into the patrone, wherein rotational forces from a motor can be selectively transmitted to the preliminary winding mechanism or the frame-by-frame film rewounding mechanism through a clutch mechanism using a planetary gear so that the two mechanisms can be driven by a single motor.
In other words, in the above-mentioned camera, at first the clutch mechanism is connected to the preliminary winding mechanism to take out the whole length of the film from the patrone and roll it round the spool, and then the motor is rotated in a reverse direction to automatically switch the clutch mechanism over to the frame-by-frame film rewinding mechanism so that the film can be rewound frame by frame into the patrone for photographing.